PSEUDOESTERS AND DERIVATIVES. XXIII. REACTION OF 3-BROMO-5-METHOXYFURAN-2(5H)-ONE WITH NUCLEOPHILES. FORMATION OF CYCLOPROPANE DERIVATIVES.

Article abstract of DOI:10.1016/S0040-4020(01)87341-5

The reactions of 3-bromo-5-methoxyfuran-2(5H)-one (1) with nucleophiles in acetonitrile, in the presence of potassium carbonate and tetrabutylammonium bromide as a catalyst, are reported.The bromofuranone 1 reacts with several carbon and oxygen nucleophiles to give the cyclopropane bis-lactones 7, 8, 11 or 12.When 1 is reacted with diethylamine or propane-2-thiol in a 2:1 ratio, similar cyclopropane bis-lactones 16 or 21, respectively, are formed.This behaviour is explained on the basis of a mechanism involving a double Michael addition, followed by ring closure via internal nucleophilic substitution of the halogen.